Carburetor air/fuel distribution control

ABSTRACT

The air valve of a dual stage carburetor has a tapered fuel metering rod secured to it and movable as a function of air valve movement to increase fuel flow; the fuel inducted passes through a hole in the air valve and splashes against a member that deflects the fuel downwardly to provide good fuel and air distribution on both sides of the valve; the splash member and air valve together act as a venturi at higher engine speed air flows to provide a greater than normal fuel metering signal at the fuel nozzle, thereby providing greater fuel delivery volume at the higher engine speeds.

United States Patent 91 Buike et a1.

[ CARBURETOR AIR/FUEL DISTRIBUTION CONTROL [75] Inventors: George W.Buike, Plymouth; William P. Haboush, 11, St. Clair Shores, both of Mich.

[73} Assignee: Ford Motor Company, Dearborn,

Mich.

[221 Filed: July 21, 1971 211 Appl. No.: 165,423

[52] US. Cl 261/50 A [51] Int. Cl. F02m 19/04 [58] Field of Search261/50 A, 50 R [56] References Cited UNITED STATES PATENTS 1,900,1913/l933 Mock 261/50 A 3,322,408 5/1967' Stoltman 261/50 A Harrison 261/50A Sweeney 261/50 A Primary ExaminerTim R. Miles Attorney-Keith L.Zerschling et a1.

[ ABSTRACT The air valve of a dual stage carburetor has a tapered fuelmetering rod secured to it and movable as a function of air valvemovement to increase fuel flow; the fuel inducted passes through a holein the air valve and splashes against a member that deflects the fueldownwardly to provide good fuel and air distribution on both sides ofthe valve; the splash member and air valve together act as a venturi athigher engine speed air flows to provide a greater than normal fuelmetering signal at the fuel nozzle, thereby providing greater fueldelivery volume at the higher engine speeds.

10 Claims, 3 Drawing Figures Patented Aug. 28, 1973 I 3,754,739

INVENTORS ATTORNEYS CARBURETOR AIR/FUEL DISTRIBUTION CONTROL Thisinvention relates, in general, to a multi-barrel, downdraft typecarburetor. More particularly, it relates to a carburetor having primaryand secondary stages of operation, the secondary stage having a fuelmetering system operably connected to an air valve.

It is a primary object of the invention to improve the air and fuel flowdistribution through the secondary throttle bore of a carburetor havinga fuel metering system of the type that varies the fuel jet area as afunction of the movement of the air valve. The invention provides a fuelflow deflection plate to'not only guide the secondary fuel flow into thethrottle bore in a manner to provide good distribution to all the enginecylinders, but the deflecting plate also at times acts as a venturi toincrease the air flow velocity at higher air flows to allow a greaterthan conventional fuel delivery at higher engine speeds.

The prior art devices that are directed to multi-barrel carburetorshaving primary and secondary stages and secondary fuel metering systemsoperable by air valves generally have only fixed attitude fuel jetnozzles so that the fuel is discharged in one direction only, with noincrease above the normal increase in fuel flow delivery volume as afunction of the increase in air flow.

It is an object of the invention, therefore, to provide a carburetorfuel and air flow deflecting member that not only guides the fuel intothe carburetor bore in an efficient manner, but also serves as a venturiat high air flows to increase the air flow velocity past the fuel jet ina manner providing a greater delivery of fuel.

Other objects, features and advantages of the invention will become moreapparent upon reference to the succeeding detailed description thereof,and to the drawings illustrating a preferred embodiment thereof;wherein, a

FIG. 1 is a top plan view of a multi-barrel carburetor embodying theinvention; 1

FIG. 2 is a cross-sectional view of a portion of the air horn section ofthe carburetor of FIG. 1 taken on a plane indicated by and viewed in thedirection of the arrows 2-2 of FIG. 1; and, I

FIG. 3 is a perspective side view of the carburetor of FIG. 1, withparts broken away and in section, illustrating the invention in adifferent operative position than that shown in FIG. 2.

FIGS. 1 and 2 show the outline and a portion of the air horn section,respectively, of a conventional, except for the invention, four barrelcarburetor of the downdraft type. It contains two primary throttle bores12 that are closed at times by a conventional choke plate 14. The latteris fixed for rotation with a shaft 16 rotatably mounted in thecarburetor body walls. The carburetor also contains a pair of secondarybores 18, flow through both being controlled by an air valve 20. Thelatter is fixed for rotation with a shaft 22 also rotatably mounted inthe walls of the carburetor body. The carburetor body portion 24dividing the primary and secondary bores is cast at its lower end toprovide an angled secondary fuel passage 24 that leads from aconventional fuel bowl, not shown.

The remaining details of construction and operation of the carburetorper se are not given since they are known and believed to be unnecessaryfor an understanding of the invention. Suffice it to say that thecarhole 30 to the far side of air valve 20 to provide better buretorwould have the usual main fuel metering system leading from the fuelbowl to the primary bores 12 for supplying fuel to the engine during lowspeed and low air flow operation thereof. The fuel supply to thesecondary throttle bores 18 for operation during higher engine speedsand air flows is supplied through the fuel passage 24, in a manner nowto be described.

The air valve 20 in general is of conventional construction. It is aplate fixed to shaft 22 in an unbalanced manner so as to be responsiveto the forces of air acting thereon when the throttle valves, not shown,located below in the carburetor, are opened to admit secondary air andfuel into the engine proper.

The underside of air valve plate 20 is provided with an ear or socket 26to which is hingedly mounted the end of a tapered fuel metering rod 28.The metering rod in turn slidably projects through the upper opening ofthe fuel passage 24 so as together with the fuel passage define a fueljet or nozzle 29 that varies in area as a function of the movement ofthe air valve.

That is, as the air valve rotates in a clockwise direction to increasethe flow of air into the engine, the tapered metering rod 28 will bemoved inwardly into the fuel passage 24 to increase the annular area ofthe fuel jet nozzle between the walls of the rod and passage, therebypermitting an increasingly greater volume of fuel to be inducted intothe secondary bores or passages 18 as the air valve opens.

As thus far described, the construction is conventional. With the fueljet nozzle 29 directed diagonally upwardly at an attitude as shown inFIG. 2, however, it will be evident that fuel being inducted frompassage 24 will spew outwardly into bore 18 and splash against theunderside of plate 20. It will be equally clear that no fuel will bepermitted to pass to the upstream or far side of air valve vplate 20 sothat as the air valve reaches an essentially vertical position, fuelwill flow down through essentially only half of the throttle bore area.This results in poor distribution of fuel and air to the intake manifoldof the engine and to the individual engine cylinders, resulting ininefficient engine operation.

To obviate the above disadvantage, the air valve plate 20 is providedwith a hole, aperture or opening 30 over each throttle bore alignedessentially with the discharge outletof fuel nozzle 29. Fuel nowdischarged from the nozzle passes in a fan shape spray throughdistribution of the fuel flow into the main induction passage 18.

However, to prevent undue fogging of the fuel spray on the far side ofplate 20, which again would result in unequal distribution of fuel andair to the engine cylinders, it is necessary that the fuel not bepermitted a free distribution, but that it be directed downwardly to amore advantageous attitude to assure an essentially equal distributionthroughout the bore of fuel on both sides of the valve plate 22.

Accordingly, an essentially dome or hat-shaped fuel deflecting member 32is attached to the air valve plate 20 over each of the holes orapertures 30 to deflect the fuel downwardly into the throttle bores inthe most advantageous direction providing the best distribution of fueland air flow into the intake manifold. The deflecting member in thiscase consists essentially of an inverted open end channel-shaped member.

In addition to serving as a fuel deflecting member, each member 32 alsoacts as a venturi at higher air flows at higher engine speeds toincrease the fuel metering signal acting on the fuel nozzle 29 tothereby increase the fuel delivery volume at this time. The lattereffect is more clearly shown in FIG. 3 where it can be seen that whenair valve plate 20 is rotated nearly to its vertical position indicatingessentially wide open throttle operation, the deflector plates are thenessentially aligned with the air flow direction so that a maximumventuri effect is accomplished, as indicated by the arrows. Theincreased air velocity through the venturi creates an even greaterdepression at the fuel jet nozzle 29 to effect a greater than normaldelivery of fuel at this time.

The operation is believed to be clear from the above description, and,therefore, is not repeated. From the foregoing, it will be seen that theinvention improves the fuel and air distribution through the secondarybores of a multi-barrel air valve type carburetor by guiding the fuel inan efficient manner, and increasing fuel delivery volume at high enginespeeds.

We claim:

I. A carburetor air/fuel mixture flow control device for use in acarburetor having an air/fuel induction passage, with an air inlet atone end and connected to an engine intake manifold at the other end, thepassage having a valve rotatably mounted thereacross for movementbetween positions opening and closing the passage, a fuel passage outletopening into the passage adjacent and below the valve, fuel meteringmeans secured to the valve and projecting into the fuel outlet in amanner to vary the quantity of fuel flow inducted into the passage as afunction of the rotative position of the valve, and fuel and air flowdirecting means secured to the valve for rotative movement with it fordirecting the flow of fuel and air into the passage in a manner tomaximize air/fuel mixture distribution through the passage, the valvehaving an aperture therein for passage therethrough of fuel inductedinto the passage, the directing means comprising deflecting means in thepath of the fuel inducted to be engaged by the fuel and deflect the fueldownwardly into the passage.

2. A control device as in claim 1, the deflecting means comprising anopen end dome shaped hollow channel-like member overlying the aperturein the valve, the deflecting means also constituting a venturi at higherair flows when the valve is rotated towards an open position forincreasing the flow velocity of the air therethrough to thereby induct agreater fuel flow at higher air flows at higher engine speeds.

3. A control device as in claim 1, the deflecting means preventingsplashing of fuel against the walls of the induction passage by causingfuel to be splashed against the deflecting means and redirecteddownwardly at an attitude providing uniform distribution throughout thepassage.

4. A carburetor air/fuel mixture flow control device for use in acarburetor having an air/fuel induction passage, with an air inlet atone end and connected to an engine intake manifold at the other end, thepassage having a valve rotatably mounted thereacross for movementbetween positions opening and closing the passage, a fuel passage outletopening into the passage adjacent and below the valve, fuel meteringmeans secured to the valve and projecting into the fuel outlet inamanner to vary the quantity of fuel flow inducted into the passage as afunction of the rotative position of the valve, and fuel delivery volumeincreasing means mounted on the valve for movement therewith forincreasing fuel flow at higher air flows upon rotation of the valve toan increased air flow position, said fuel delivery volume increasingmeans including a hole in the valve aligned with the fuel outlet forinduction of fuel through the hole into the passage, and venturi meanssecured to the valve over the hole whereby air passing through theventuri at increased air flows upon opening rotative movement of thevalve increases the fuel delivery volume.

5. A control device as in claim 4, the venturi being defined by an openend inverted channel shaped member overlying the hole and directing fuelsplashed thereagainst downwardly towards the center of the passage.

6. A control device as in claim 5, the splash surface of the memberbeing essentially at right angles to the diredtion of fuel flow from thefuel outlet.

7. A control member as in claim 4, the venturi means being secured tothe upstream side of the valve.

8. A carburetor fuel and air flow control member comprising, an airvalve rotatable mounted across a carburetor induction passage, thelatter having a fuel outlet port downstream of the valve, the valvehaving a tapered fuel metering rod movable with the valve variablyin'to'the fuel outlet to constitute a variable area fuel jet, the valvehaving an opening aligned with the flow of fuel from the jet into thepassage so as to permit the passage of the fuel therethrough, and a fuelflow directing means and fuel volume control member secured to the valveon the upstream side of the valve over the opening for deflecting thefuel flow downstream towards the center of the induction passage tominimize fuel fogging while providing good distribution of fuel and airthroughout the passage.

9. A control member as in claim 8, the control member consisting of aninverted channel shaped member covering the opening and constituting asplash surface for the fuel.

10. A control member as in claim 8, the control member consisting of adome like member open at its ends and covering the opening to define aventuri operable at higher air flows to increase the velocity of airpassing through the venturi to increase the fuel metering inductionsignal on the fuel jet to increase fuel flow at this time.

1. A carburetor air/fuel mixture flow control device for use in acarburetor having an air/fuel induction passage, with an air inlet atone end and connected to an engine intake manifold at the other end, thepassage having a valve rotatably mounted thereacross for movementbetween positions opening and closing the passage, a fuel passage outletopening into the passage adjacent and below the valve, fuel meteringmeans secured to the valve and projecting into the fuel outlet in amanner to vary the quantity of fuel flow inducted into the passage as afunction of the rotative position of the valve, and fuel and air flowdirecting means secured to the valve for rotative movement with it fordirecting the flow of fuel and air into the passage in a manner tomaximize air/fuel mixture distribution through the passage, the valvehaving an aperture therein for passage therethrough of fuel inductedinto the passage, the directing means comprising deflecting means in thepath of the fuel inducted to be engaged by the fuel and deflect the fueldownwardly into the passage.
 2. A control device as in claim 1, thedeflecting means comprising an open end dome shaped hollow channel-likemember overlying the aperture in the valve, the deflecting means alsoconstituting a venturi at higher air flows when the valve is rotatedtowards an open position for increasing the flow velocity of the airtherethrough to thereby induct a greater fuel flow at higher air flowsat higher engine speeds.
 3. A control device as in claim 1, thedeflecting means preventing splashing of fuel against the walls of theinduction passage by causing fuel to be splashed against the deflectingmeans and redirected downwardly at an attitude providing uniformdistribution throughout the passage.
 4. A carburetor air/fuel mixtureflow control device for use in a carburetor having an air/fuel inductionpassage, with an air inlet at one end and connected to an engine intakemanifold at the other end, the passage having a valve rotatably mountedthereacross for movement between positions opening and closing thepassage, a fuel passage outlet opening into the passage adjacent andbelow the valve, fuel metering means secured to the valve and projectinginto the fuel outlet in a manner to vary the quantity of fuel flowinducted into the passage as a function of the rotative position of thevalve, and fuel delivery volume increasing means mounted on the valvefor movement therewith for increasing fuel flow at higher air flows uponrotation of the valve to an increased air flow position, said fueldelivery volume increasing means including a hole in the valve alignedwith the fuel outlet for induction of fuel through the hole into thepassage, and venturi means secured to the valve over the hole wherebyair passing through the venturi at increased air flows upon openingrotative movement of the valve increases the fuel delivery volume.
 5. AcontrOl device as in claim 4, the venturi being defined by an open endinverted channel shaped member overlying the hole and directing fuelsplashed thereagainst downwardly towards the center of the passage.
 6. Acontrol device as in claim 5, the splash surface of the member beingessentially at right angles to the diredtion of fuel flow from the fueloutlet.
 7. A control member as in claim 4, the venturi means beingsecured to the upstream side of the valve.
 8. A carburetor fuel and airflow control member comprising, an air valve rotatable mounted across acarburetor induction passage, the latter having a fuel outlet portdownstream of the valve, the valve having a tapered fuel metering rodmovable with the valve variably into the fuel outlet to constitute avariable area fuel jet, the valve having an opening aligned with theflow of fuel from the jet into the passage so as to permit the passageof the fuel therethrough, and a fuel flow directing means and fuelvolume control member secured to the valve on the upstream side of thevalve over the opening for deflecting the fuel flow downstream towardsthe center of the induction passage to minimize fuel fogging whileproviding good distribution of fuel and air throughout the passage.
 9. Acontrol member as in claim 8, the control member consisting of aninverted channel shaped member covering the opening and constituting asplash surface for the fuel.
 10. A control member as in claim 8, thecontrol member consisting of a dome like member open at its ends andcovering the opening to define a venturi operable at higher air flows toincrease the velocity of air passing through the venturi to increase thefuel metering induction signal on the fuel jet to increase fuel flow atthis time.